C#, override Equals() & operator==, list<obj>.contains will not return true.

I have a class where I have overridden "==" and "Equals()", which does work to return true when comparing two different IntVector2's with identical values.

However, I try using it as a Key in a dictionary, and it will not return anything, so I have to use the following code to get the object reference I want.

				IntVector2 iv = new IntVector2(x, y);
				foreach(IntVector2 iv2 in this.HeightMap.Keys)
				{
					if(iv2 == iv) 
					{
						iv = iv2;
						break;
					}
				}

What do I need to do so a dictionary can use a custom object as a key like this?

public class IntVector2
{
	public int X = 0;
	public int Y = 0;
	public IntVector2 (int x, int y)
	{
		this.X = x;
		this.Y = y;
	}

	public static bool operator ==(IntVector2 v1, IntVector2 v2)
	{
		return (v1.X == v2.X) && (v1.Y == v2.Y);	
	}
	public static bool operator !=(IntVector2 v1, IntVector2 v2)
	{
		return (v1.Y != v2.Y) || (v1.X != v2.X);	
	}
	public override bool Equals (object obj)
	{
		if(obj is IntVector2)
		{
			IntVector2 v1 = (IntVector2)obj;
			return (v1.X == this.X) && (v1.Y == this.Y);
		}
		return false;
	}
	
}